ading some constants used in pow new impl
better accuracy with pow function
Merge branch 'master' into improving_pow
factorizing some code and using load to make the lookup work
it's better to make the work done by pow_abs and let pow just deal with a possible a0<0
bug in exhaustive expx2 test
small correction in nthroot and test added
Merge branch 'master' into improving_pow
stirling for single no more uses double
Merge pull request #723 from jtlap/improving_pow

Improving pow